This invention relates to valve actuators in general and more particularly to a valve actuator employing a unique housing configuration and mechanism for operating a water valve or other valve in a reliable and economical manner.
Essentially, the prior art is replete with numerous devices which serve to operate in conjunction with valves to enable the operation of such valves when necessary. In regard to valve actuators, there are many examples of actuators which are employed in various types of systems. For example, in fire protection systems valves may be employed to open a water conduit during a fire or during an emergency. The fire codes require that the opening be relatively slow in that the valve should not be capable of being opened or closed in less than 5 seconds. In any event, many of the valve actuators are associated with additional functions such as the sounding of an alarm when the valve is operated and hence are associated with limit switches. These limit switches must be accurately operated when the valve is operated in order to obtain the above described characteristics.
Valve actuators based on their required operation should be rugged and reliable in operation. As one can ascertain, a valve actuator may not be called upon to operate for extended periods of time. Hence the actuator should be capable of functioning after a long period of non use. Thus the device should be reliable in construction and should be protected against deleterious elements in the environment so as not to rust or jam or otherwise deteriorate with age.
Based on the prior art, many valves were made by machining processes which utilized relatively expensive materials such as cast iron or stainless steel. In this manner the valve bodies were cast and then machined to required dimensions. Thus the prior art fabrication of valve actuators resulted in a relatively expensive component. Based on the type of materials that were utilized, the actuators had to be constantly maintained in regard to lubrication of the same and in general in regard to a predetermined maintenance plan where the valve actuator would constantly be tested to assure that they would operate when required to do so.
It is, therefore, an object of the present invention to provide a valve actuator which is simple, inexpensive and rugged in construction.
The valve actuator to be described includes a pivot arm which is contained in a stamped metal housing. The pivot arm as will be explained is associated with a pivot nut which causes the arm to pivot upon actuation of a spindle. Based on the construction, the resultant valve actuator is extremely rugged, requires very little machining and hence is relatively inexpensive while being extremely reliable in operation.